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70 CJ5 Disc brake conversion question.

Discussion in 'Early CJ5 and CJ6 Tech' started by texaspyro, Sep 6, 2008.

  1. Sep 6, 2008
    texaspyro

    texaspyro New Member

    DFW
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    Whats up everyone? Last week I purchased a 1970 CJ from a friend of mine. It came with the stock drum brakes. I have read and read about doing the disc brake conversion. It seemed pretty straight forward.... Until today... I went to the scrap yard and pulled some brackets off, and calipers off an 83 k5 blazer. I got home tore into my jeep pulled the old parts off and bolted the new bracket right up. At this point I was pretty excited that this actually may be easy... So I called around and found a parts store on the other side of the metroplex that had a pair of brake rotors form a 78 CJ. I went down there and picked them up along with some new calipers. I get home all excited to bolt them up to my hubs and they don't fit!!!! My hubs appear to be stock hubs. They measure 4 1/8" inside the lugs. The rotor measures 3 5/8" on the big hole that's supposed to slide over the hub. Anybody have any suggestions on what to do? I'd hate to go down and have them machined and have some other problem with them lining up with the caliper. As far as I know it is the stock Dana 27. Any help would be most appreciated!
     
  2. Sep 6, 2008
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    The rotors fit on the back side of the hub. The hubs need to be machined to fit the rotor. However, having said that, I don't have the rotor id measurement handy to verify you have the right rotor. Maybe someone can chime in.....
     
  3. Sep 6, 2008
    texaspyro

    texaspyro New Member

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    On the back side of the hub?? So i would have to press out the old studs on the hubs and press in new ones on the rotor? I guess I missed that little step...:rofl:
     
  4. Sep 7, 2008
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    Yup. Need new studs especially for disc brakes. The studs go through the rotor first then press in tight to the hub holding the assembly together. Just need ones for the '78 CJ with disc brakes.
     
  5. Sep 7, 2008
    trickpatrick

    trickpatrick Done? LOL

    North Idaho USA
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    I did this.
    be careful about pressing out the studs.
    You can ruin the hub.
    And you need different studs with the shoulder in the back for the disk and then the splines.
    But using the d27 hubs is good because of the 6 bolt locking hubs..
     
  6. Sep 7, 2008
    texaspyro

    texaspyro New Member

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    OK, so I mounted the discs on the back side of the hubs...duh...I guess im loosing my mind. Anyway everthing seems to mount up great.. With the exception of the discs rubbing the caliper bracket. It seems that the whole assembly need to be spaced out and 1/8th or so. Any more suggestions. Thank Y'all so much for the help.
     
  7. Sep 7, 2008
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    Yup. I don't remember the whole part # but the last two digits of your inner bearing race should be 10. You need the thicker race, same exact # except the last two digits are 11. This will space the hub out like you need. I'd recommend using national seal # 8430s. You won't be able to drive it in all the way due to the bearing being spaced out, but this seal will stay in place. You want to drive it in until just before the lip of the seal rubs on the bearing.
     
  8. Sep 7, 2008
    texaspyro

    texaspyro New Member

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    So I take it that adding a 1/8" spacer of some sort wont work?
     
  9. Sep 7, 2008
    jayhawkclint

    jayhawkclint ΜΟΛΩΝ ΛΑΒΕ

    Oklahoma City, USA
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    Had the same problem on my '70. Had to use Timken part #LM501311 on my D27. Part #LM501310 that Nickmil mentioned above I think is for D30. It's just a thicker race, same cone and bearing. Here's the thread: http://www.earlycj5.com/forums/showthread.php?t=33352
     
  10. Sep 7, 2008
    texaspyro

    texaspyro New Member

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    OK, so I decided that before I ordered the different wheel bearings and races that I would mock up a 1/16" spacer to go between the bearing and the spindle. I turned out that that was exactly the amount of space that I needed. But..... When I went to reassemble the whole thing I discovered that I could no longer get the snap ring to snap back over the axle. So I don't think that the bearing idea will work for my application. I guess tomorrow I'll call around to so machine shops and see if the can machine 1/16th or a tad more off the back of the hubs.... And it continues... I cant wait to start the power steering conversion next week...:rofl: Time for a few of these..:beer:
     
  11. Sep 7, 2008
    w3srl

    w3srl Semi-homeless in Florida Staff Member

    Port Orange, FL
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    I wouldn't lose sleep over the snap ring, it's not really necessary IMHO.

    BTW- I would get the correct bearing race rather than mickey-mousing a spacer in there, but hey that's just me. :)
     
  12. Sep 7, 2008
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    :iagree:

    I've been running my front ends for close to 20 years without the snap rings with no issues. If you got room for it I'd run it, but you don't, so don't sweat it. I'd run the right race vs. removing more material from the hub. You don't want to weaken it....
     
  13. Sep 8, 2008
    texaspyro

    texaspyro New Member

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    Thank y'all so much for the help. I got the new bearing races today and everything bolted back up beautifully. Got my new braided lines on there, all that's left is plumbing all new lines from my power brake booster. Looking forward to starting the power Saginaw steering conversion this week. Anyone know a good source for a postal steering column? No scrap yard around here have one. Thanks again for all the help!
     
  14. Sep 8, 2008
    w3srl

    w3srl Semi-homeless in Florida Staff Member

    Port Orange, FL
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